Hopper Insert For An Asphalt Paving Machine

ABSTRACT

A hopper insert is provided for an asphalt paving machine. The hopper insert provides for passive mixing of asphalt material, and also provides a dual capacity loading option. Two upper baffles extend across an open upper end of the hopper insert. A grate extends between the upper baffles. Asphalt material is received on top of the grate between the upper baffles.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to hopper inserts for use with asphalt pavingmachines, and particularly to hopper inserts designed to promote passiveremixing of asphalt material and to minimize thermal and mechanicalsegregation of the asphalt material while retaining adequate surgecapacity.

2. Description of the Prior Art

Asphalt paving machines typically have an integral receiving hopper onthe front end of the machine which receives asphalt material which is tobe spread on the ground by the paving machine. The typical integralreceiving hopper of an asphalt paving machine has a relatively low frontwall to allow asphalt material to be dumped from a dump truck directlyinto the hopper.

Additionally, it is known to provide hopper inserts which are placed inthe integral receiving hopper of the asphalt paving machine, whichhopper inserts increase the volume of asphalt material which can becarried by the asphalt paving machine.

When using a material transfer vehicle (MTV) which is locatedintermediate between the dump truck and the paving machine, it is commonto use a hopper insert, which will have substantially higher walls andcapacity than does the integral hopper of the paving machine. Thematerial transfer vehicle (MTV) receives the asphalt material from thedump truck, and then conveys the asphalt material up an elevatedconveyor to drop it into the top of the hopper insert located on thepaving machine.

One issue which is always important to a successful asphalt paving jobis to avoid segregation of the aggregate material in the asphalt mix andto avoid thermal segregation, namely the formation of cool spots, in theasphalt mix. There is a continuing need for improvements in asphalthandling equipment to prevent or minimize both aggregate segregation andthermal segregation within the asphalt mix.

SUMMARY OF THE INVENTION

In one embodiment a hopper insert apparatus is provided for an asphaltpaving machine. The apparatus includes a perimeter wall defining ahopper insert interior, the interior having an open upper end forreceiving incoming asphalt material, and an open lower end fordischarging the asphalt material. An upper end cross-sectional area ofthe open upper end is greater than a lower end cross-sectional area ofthe open lower end. First and second upper baffles extend across thehopper insert interior and are supported from the perimeter wall. Theupper baffles are located closer to the upper end than to the lower end.The upper baffles are spaced laterally apart from each other. A grate issupported within the interior. The upper baffles extend upwardly higherthan the grate for retaining asphalt material on the grate.

In another embodiment a hopper insert apparatus is provided for anasphalt paving machine. The apparatus includes a perimeter wall defininga hopper insert interior, the interior having a larger open upper endfor receiving incoming asphalt material and a smaller open lower end fordischarging the asphalt material. A grate is located closer to the openupper end than to the open lower end. The grate is laterally spaced fromthe perimeter wall around at least a majority of the periphery of theperimeter wall.

In another embodiment a method is provided for passive mixing of asphaltmaterial with a hopper insert for an asphalt paving machine. The hopperinsert includes a larger upper open end and a smaller lower open end sothat the hopper insert is funnel shaped. The method may include thesteps of:

(a) receiving the asphalt material on top of a grate located nearer tothe upper end than to the lower end of the hopper insert;

(b) reducing an average clump size of the asphalt material as at least aportion of the asphalt material passes through the grate; and

(c) discharging the asphalt material out the smaller lower open end ofthe hopper insert onto a conveyor of the asphalt paving machine.

The grate may include a plurality of parallel grate bars spaced apartfrom each other by a spacing in a range of from about 3 inches to about8 inches.

The grate bars may extend transversely between the first and secondupper baffles.

The grate may define an upper grate surface located at least 6 inches,more preferably at least 12 inches, and most preferably at least about18 inches, lower than an uppermost extent of the central portions of theupper baffles so that asphalt material may be piled upon the grate to adepth of at least 6 inches, more preferably at least 12 inches, and mostpreferably at least 18 inches.

The grate may be superimposed over a majority of, or over the entirelower end of the hopper insert apparatus.

The grate may be spaced from the perimeter wall so that at least onegrate bypass is defined between the grate, the perimeter wall and theupper baffles.

The central portion of each of the upper baffles may have a lower edgelocated lower than the open upper end.

The first and second upper baffles may flare downwardly away from eachother.

The lateral spacing between the first and second upper baffles may varyalong the length of the upper baffles.

The perimeter wall may include a front wall portion and a rear wallportion, and the upper baffles may have front and rear ends supportedfrom the front and rear wall portions, respectively.

The perimeter wall may include four major walls joined together at theirlower ends to define a four sided opening having four lower corners. Thefour major walls may slope away from each other along at least a part ofa wall height from their lower ends toward their upper ends. Four lowerbaffles may be located above the four lower corners, respectively, witheach lower baffle covering one of the lower corners and extendinglaterally inward and downward from the peripheral wall, so as to divertmaterial traveling downward toward the lower corners laterally inwardand thus across the width of the paving machine conveyor.

The perimeter wall may further include at least one corner wall joiningeach two adjacent major walls so that the open upper end is polygonalhaving at least eight sides.

The height of the asphalt material piled on top of the grate increasesthe weight forcing the asphalt material through the grate thus enhancinga reduction in average clump size of the asphalt material as it passesthrough the grate.

The grate may also capture foreign material and prevent the foreignmaterial from flowing downward into the paving machine conveyor where itmight be conveyed under the paving device and thus damage the newpavement.

The variable width spacing between the upper baffles may serve tolaterally spread the asphalt material to different widths along a lengthof the grate. This aids in avoiding the creation of a concentration ofsegregated large aggregate material adjacent the edges of the pavingconveyor located below the lower outlet of the hopper insert.

The downward outward flare between the upper baffles may reduce bridgingof the asphalt material between the upper baffles thus allowing freeflow of the asphalt material.

The upper baffles may function as retainer walls which provide anarrangement which allows a user to selectively fill the hopper insert toone of two optional fill levels. The first optional smaller fill levelinvolves depositing the asphalt material only between the two retainerwalls without allowing the asphalt material to overflow the retainerwalls. The second larger optional fill level involves allowing theasphalt material to overflow the retainer walls so that the depositedasphalt material is also received within a lateral volume between eachof the retainer walls and the peripheral wall of the hopper insert.

By forming the grate as an island grate, bypass zones are defined onopposite sides of the island grate but still between the upper bafflesso as to allow a flow path for asphalt material in the event of bridgingof the asphalt material on top of the grate or some portion thereof.

Numerous objects, features and advantages of the present invention willbe readily apparent to those skilled in the art upon a reading of thefollowing disclosure when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the various equipment utilized in anasphalt paving job, including a dump truck, a material transfer vehicle,and an asphalt paving machine including a hopper insert.

FIG. 1A is a schematic plan view of the integral receiving bin or hopperof an asphalt paving machine, showing the conveyor opening of theasphalt paving machine.

FIG. 2A is a schematic perspective view of one embodiment the hopperinsert of the present invention in which the upper baffles extend abovethe open upper end of the hopper insert.

FIG. 2B is a schematic perspective view of another embodiment the hopperinsert of the present invention in which the upper baffles do not extendabove the open upper end of the hopper insert.

FIG. 3A is a top plan view of the hopper insert of FIG. 2A. The grate ispeninsula shaped having one bypass zone adjacent the grate.

FIG. 3B is a top plan view of the hopper insert of FIG. 2B. The grate isisland shaped having two bypass zones on opposite sides of the grate.

FIG. 4 is a cross-section elevation view taken along line 4-4 of FIG.3A.

FIG. 5 is a right side elevation view of the hopper insert of FIG. 2A.

FIG. 6 is a cross-section view similar to FIG. 4 schematicallyillustrating the hopper insert filled to a first optional lower filllevel wherein the asphalt material is not allowed to overflow the upperbaffles.

FIG. 7 is a view similar to FIG. 6 showing the hopper insert filled to asecond optional larger fill level wherein the asphalt material isallowed to overflow the upper baffles.

FIG. 8 is a schematic right side elevation view showing an upper hopperextension.

FIG. 9 is a schematic right side elevation view showing an activeremixing module mounted below the hopper insert.

FIG. 10 is a schematic plan view of the active remixing module of FIG.9.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates the major items of equipment utilizedin an asphalt paving job. A dump truck 10 is shown depositing asphaltmaterial into a receiving bin 12 of a material transfer vehicle 14.

The material transfer vehicle 14 conveys the asphalt material up a firstconveyor 16 to a second conveyor 18. Material exits the upper end 20 ofthe second conveyor 18 into a hopper insert 22 constructed in accordancewith the present invention. The hopper insert 22 is received within anintegral hopper 24 on the front of an asphalt paving machine 26. Theasphalt paving machine 26 has a horizontally extending conveyorschematically indicated at 28 which runs under the bottom of theintegral hopper 24 and carries the asphalt material to the rear of thepaving machine 26 where the asphalt material is laid down to form anewly laid asphalt layer 30.

As schematically illustrated in FIG. 1A, the integral hopper 24 of thematerial transfer vehicle 26 may have a floor 62 with a conveyor opening64 formed therein. The paving machine conveyor 28 may include twoparallel chain flight conveyors 28A and 28B. Each chain flight conveyorincludes a pair of parallel spaced chains such as 65 having a pluralityof flight bars such as 66 extending therebetween. The flight bars 66 arecarried from front to rear by the moving chains 65 so that the flightbars 66 slide across a fixed conveyor plate 68 to convey the asphaltmaterial from front to rear through the paving machine 26. The chains 65may be covered by chain cover members such as 70 to protect them fromthe particulate material. Typical openings 64 may have a width 67 ofapproximately 48 inches and a length 69 of approximately 54 inches.

Details of construction of one embodiment of the hopper insert 22 areshown in FIGS. 2A, 3A, 4 and 5. A second embodiment of the hopper insert22 illustrating several optional features is seen in FIGS. 2B and 3B. Inthe embodiment of FIGS. 2A and 3A, the upper baffles extend above theupper edge of the hopper insert, whereas in the embodiment of FIGS. 2Band 3B the upper baffles are located lower within the interior of thehopper insert. In the embodiment of FIGS. 2A and 3A, the grate ispeninsula shaped, whereas in the embodiment of Fibs. 2B and 3B the grateis island shaped. Also, in the embodiment of FIGS. 2A and 3A there aremore grate bars which are spaced closer together than is the case in theembodiment of FIGS. 2B and 3B. For similar components of the twoembodiments, the same identifying numerals are used in the Figures.

The hopper insert 22 includes a perimeter wall 32 defining a hopperinsert interior 33 having an open upper end 34 and an open lower end 36.The perimeter wall 32 includes a front wall portion 38, a rear wallportion 40, a left side (from the perspective of the operator of thepaving machine 26) wall portion 42, a right side wall portion 44, a leftfront corner wall portion 46, a right front corner wall portion 48, aright rear corner wall portion 50, and a left rear corner wall portion52.

The front wall portion 38, rear wall portion 40, left side wall portion42, and right side wall portion 44 may be generally referred to as fourmajor wall portions. By the term “major wall portion” it is meant thatthese four wall portions have a longer perimeter on their upper edgesthan do the other wall portions. In one embodiment, the four major wallportions may be rectangular plates. In another embodiment they may betrapezoidal in shape. In another embodiment each of the side wallportions such as 44 may be made of two triangular plates such as 44A and44B seen in FIG. 5

In an embodiment, the four corner wall portions 46, 48, 50 and 52 may betriangular shaped plates as shown.

The open upper end 34 may be polygonal in shape having eight sides. Thelower open end 36 may be four sided. With the use of the lower baffles56 described below, the lower open end 36 may be considered to be eightsided.

As seen in FIG. 5, the hopper insert 22 may include an upper extensionplate or back plate 41 on the rear wall portion 40 extendingsubstantially vertically upward above the top edge of the perimeter wall32. The back plate 41 serves as a back stop to retain asphalt materialin the hopper insert 22 when that material is being fed into the hopperinsert 22 from the conveyor 18 of the material transfer vehicle 14.

A generally horizontal extending lower flange 54 may extend outward fromnear the lower end of the perimeter wall 32 to provide a base forsupporting the hopper insert on the floor 62 of the integral hopper 24of the paving machine 26. The lower edge of the perimeter wall 32 mayextend slightly below the flange 54 to aid in centering the hopperinsert 22 in the opening 64 of the paving machine conveyor 28 seen inFIG. 1A. The lower flange 54 may also support the hopper insert on topof the active remixing module 122 described below with regard to FIGS.9-10.

The four major walls 38, 40, 42 and 44 may be joined together at theirlower ends to define the open lower end 36 of the hopper insert 22 as afour sided opening having four lower corners 55A, 55B, 55C and 55D, asseen in dashed lines in FIG. 3B.

In the embodiment of FIG. 3B optional flow diverters 41 and 43 are shownbetween the lower ends of front wall portion 38 and rear wall portion40. These flow diverters are not present in the embodiment of FIG. 3A.

As best seen in FIG. 4, the four major walls slope away from each otheralong at least a part of a wall height 54 from their lower ends towardtheir upper ends so that the open upper end 34 is larger than the openlower end 36. Located above each of the four corners 55A, 55B, 55C and55D are lower baffles 56A, 56B, 56C and 56D, respectively, each of whichcovers one of the lower corners and extends laterally inward anddownward from the peripheral wall 32. These lower baffles 56A-D serve todivert any material traveling downward in the area of the corners 55A-Dlaterally inward across the width of the lower opening 36.

Each of the lower baffles 56 may be formed from a generally trapezoidalshaped steel plate welded to the inner surfaces of three convergingwalls. For example, the lower baffle 56C as seen in FIGS. 3A and 4, iswelded to walls 40, 50 and 44 and extends laterally inward from thosewalls over the lower corner 55C of what would otherwise be the loweropening 36 of the hopper insert.

It is noted that depending upon the size of the lower baffles 56A-D andtheir proximity to the lower end of the perimeter wall 32, the lowerbaffles 56A-D may also be considered to partially define the shape ofthe open lower end 36 in which case the open lower end 36 may beconsidered to be eight sided.

As best seen in FIG. 5, the front wall portion 38 slopes at asignificantly greater angle 57 than the rear wall portion 40, thuscreating a large front overhang area 58 to increase the capacity of thehopper insert 22. As is also apparent in FIG. 5, the height 54 of theperimeter wall 32 may decrease from the front wall 38 toward the rearwall 40 so that an upper edge 60 of the side wall such as 44 is slopeddownward from front to rear.

In one embodiment, the four sided lower opening 36 of hopper insert 22may be dimensioned to substantially correspond to typical dimensions ofthe floor opening 64 above the conveyor 28 of the paving machine 26.

The hopper insert 22 may include first and second upper baffles 76 and78 extending across the open upper end 34 of the hopper insert 22 andsupported from the front and rear wall portions 38 and 40 of perimeterwall 32. As is best appreciated in the side elevation view of FIG. 5,for the embodiment of FIGS. 2A and 3A each of the upper baffles 76 and78 includes at least a central portion 76B and 78B, respectively,extending higher than the upper edge 60 of the perimeter wall 32.

As is best seen in the plan views of FIGS. 3A and 3B, the upper baffles76 and 78 and particularly their central portions 76B and 78B are spacedtransversely away from the perimeter wall 32 and particularly from thecorresponding side walls 42 and 44, respectively, of the perimeter wall32. This defines lateral volumes 80 and 82, respectively, within theperimeter wall 32 between the upper baffles 76 and 78 and portions ofthe perimeter wall 32.

As also seen in FIGS. 3A and 3B, the first and second upper baffles 76and 78 define an interior portion 84 of the cross-sectional area of theinterior 33 adjacent the open upper end 34 having an interior portioncross-sectional area less than the upper end cross-section area of theopen upper end 34.

As seen in FIGS. 3A and 4, a grate 86 covers at least a part of theinterior portion 84 of the open upper end 34. The grate 86 may include aplurality of parallel grate bars 88 spaced apart from each other by aspacing 90 which preferably is in a range of from about 3 inches toabout 8 inches, and more preferably in a range of from about 4 inches toabout 6 inches. In the embodiments illustrated in FIGS. 3A and 3B, thegrate bars 88 extend transversely between the first and second upperbaffles 76 and 78. The embodiment of FIG. 3A illustrates 16 grate barsat a 4 inch grate spacing. The embodiment of FIG. 3B illustrates 10grate bars at a 6 inch grate spacing. In general, the grate 86 may bedescribed as having at least six grate bars 88, and more preferably atleast eight grate bars, and most preferably at least ten grate bars.

Although the grate bars 88 are shown in the illustrated embodiments asextending transversely between the generally lengthwise arranged upperbaffles 76 and 78, other patterns and arrangements of the grate bars 88may be used. For example, the grate bars 88 could run lengthwisesubstantially parallel to the central portions of the baffles 76 and 78with the forward and rearward ends of the grate bars being supported bya suitable cross member extending between the baffles 76 and 78.Optionally, the grate bars could be oriented obliquely relative to thelength or width of the hopper insert 22. Optionally, the grate 86 doesnot have to be constructed simply with parallel grate bars, but thegrate could be arranged in a grid or other pattern. The controllingfactor is to provide an arrangement with appropriate spacing and shapesof spacing between the grate bars so that any clumps in the asphaltmaterial will break and pass through the grate bars.

The baffles 76 and 78 may also be referred to as first and second grateboundary walls 76 and 78 or as opposed lateral retaining walls 76 and78, extending along opposite sides of the grate 86 and attached toopposite sides 38 and 40 of the peripheral wall 32. The baffles 76 and78 retain the asphalt material piled on top of the grate 86.

As best seen in FIG. 4, the grate 86 defines an upper grate surface 92which is preferably located a distance 94 of at least 6 inches, morepreferably at least 12 inches, and most preferably about 18 inches,below an uppermost extent or upper edge 96 of the central portion of theupper baffles 76 and 78.

As is best seen in FIG. 3A, the grate 86 may be dimensioned so that itis superimposed over a majority of the open lower end 36 of the hopperinsert 22. More preferably the grate 86 may be superimposed over atleast about 80%, and even more preferably at least about 90% of the openlower end 36. The grate 86 may be superimposed over the entire openlower end 36.

Preferably, the grate 86 is spaced from the perimeter wall around atleast a majority of the perimeter wall 32. In the embodiment of FIGS. 2Aand 3A, the grate may be described as a peninsula shaped grate have onegrate bypass 97 adjacent the grate.

Optionally, the grate 86, as shown in FIGS. 2B and 3B, may be an islandgrate that is spaced from the perimeter wall around the entire peripheryof the perimeter wall 32. Such an island grate creates two gratebypasses 98 and 100 on opposite sides of the grate 86 but within theinterior zone 84 between the upper baffles 76 and 78.

The bypass zones 97, 98 and 100 will allow asphalt material to bypassthe grate 86 if the grate 86 were to become plugged or bridged over withasphalt material. This ensures that a paving job can continue, even ifunder less than ideal conditions, if a bridging or plugging problemoccurs.

As best seen in FIG. 4, a lower edge such as 102 and 104 of the upperbaffles 76 and 78, respectively, and particularly of the centralportions thereof are located at a distance 106 lower than the upper edge60 of the open upper end 34 closest to any respective portion of theupper baffles.

As is also shown in FIG. 4, the first and second upper baffles 76 and 78flare downwardly away from each other. This aids in preventing asphalticmaterial from plugging over or bridging the grate.

As best seen in FIGS. 3A and 3B, a transverse spacing generallyidentified as 108 between the upper baffles 76 and 78 varies along alength of the upper baffles 76 and 78, that is in the direction fromfront to rear or rear to front of the hopper insert 22.

In the embodiments illustrated, each of the upper baffles 76 and 78 maybe formed from a bent plate of steel, wherein central portions 76B and78B of the baffles run substantially front to rear and are parallel toeach other. Forward portions 76A and 78A, and rearward portions 76C and78C of each baffle are bent laterally inward toward the opposed bafflesuch that starting from front to rear, the transverse spacing 108between baffles 76 and 78 increases from the front wall portion 38toward the rear, until the central portions 76B and 78B of the bafflesare reached, at which point the spacing 108 becomes constant across thecentral portion of the hopper insert 22, and then the spacing 108becomes smaller as the rear wall 40 is approached. This arrangement aidsin preventing aggregate material from gathering in a straight lineadjacent the lower lengthwise sides of the bottom opening 36 and ingeneral spreads any segregated aggregate over the width of the hopperinsert 22 as the aggregate flows downward through the hopper insert 22.The upper baffles may also be formed of multiple sheets of materialjoined together.

In the embodiments illustrated in FIGS. 3A and 3B the front and rearends of the baffles 76 and 78 are attached to the front and rear wallportions 38 and 40, respectively, of the perimeter wall 32. Theattachment of baffles 76 and 78 to the wall portions may be by bolts orother suitable fasteners to attach the baffles to mounting tabs such as109 welded on the interior of the perimeter wall 32. Additionally,lateral braces such as 110 may extend between the side walls 40 and 44and the adjacent upper baffles.

An alternative lower mounting position for the grate 86 and upperbaffles 76 and 78 is shown in FIG. 2B. There it is seen that the grate86 and upper baffles 76 and 78 may be mounted so that the upper edges ofthe central portions of the baffles 76 and 78 are substantially parallelto and in the same plane as the upper edge 60 of the perimeter wall 32.This provides a lower capacity fill mode and can be achieved simply byproviding lower mounting tabs 109 as seen in FIG. 2B.

Passive Remixing

As will be understood by those skilled in the art, asphalt material iscomprised of an asphaltic binder mixed with sand and aggregate materialsof various sizes. When the asphalt material is mixed in the asphaltproduction plant from which it is obtained by the trucks 10 shown inFIG. 1, the asphalt material has a relatively uniform distribution ofthe aggregate materials of various sizes throughout the matrix ofasphaltic binder material, and the asphalt material has been heated to arelatively uniform temperature throughout the mixture.

The hot uniform asphalt mixture is then deposited in the trucks 10 whichmust carry it as quickly as possible to the job site. Two things happenduring transport of the asphalt material and during handling of theasphalt material as it is transferred into the truck 10, then from thetruck 10 to the material transfer vehicle 14, then from the materialtransfer vehicle 14 to the asphalt paving machine 26. The material willbe subject to non-uniform cooling, particularly while it is sitting inthe bed of the truck 10. This problem is exacerbated if the truck 10must travel a long distance to the job site or if traffic delays areencountered. This non-uniform cooling of the asphalt mixture will allowrelatively cool crusts or clumps to form on the surface and the sides ofthe piled up asphalt material.

Additionally, as the asphalt material is handled, it tends to segregate,and particularly the larger aggregate material at the top of the pilewill tend to roll down sloped surfaces of the pile and tend to gatheralong the edges of any container or conveying device.

Thus it is desirable to avoid such physical and thermal segregation ofthe asphalt material as it is handled. Through appropriate design thesegregation process can even be reversed so that the asphalt material isremixed as it is handled.

Numerous features of the hopper insert 22 contribute to passive remixingof the asphalt material as it flows downward through the hopper insert22.

First, by depositing the asphalt material on top of the grate 86 andthen piling additional asphalt material on top of the grate to increasethe pressure on the material resting on the immediate top surface 92 ofthe grate 86, any larger clumps of material which have formed during thetransport procedure will tend to be broken apart by the grate 86 therebyreducing the average size of any clumps of asphalt material as thematerial flows through the grate 86. To that end, the upper edges of thegrate bars 88 are preferably relatively sharp edges to aid in breakingapart the clumps of asphalt material.

Also, as any clumped asphalt material is broken into smaller clumps,this will reduce thermal segregation of the material as the smallerclumps can more easily absorb heat from surrounding hotter asphaltmixture as the material flows downward through the hopper insert 22.Thus clump size reduction and remixing are achieved passively, and theexpense of active remixing equipment may often be avoided.

Additionally, the variable width 108 between the upper baffles 76 and 78prevents any collection of larger aggregates against the upper bafflesfrom being aligned with the length of the hopper insert 22 and thus withthe left and right edges of the lower opening 36 thereof. Thisdistributes any such collected aggregate material over a portion of thewidth of the hopper insert.

Additionally, if the hopper insert 22 is loaded in a first lowercapacity mode as further described below with regard to FIG. 6, thelength of the slope on top of the aggregate pile is reduced at least inthe lateral direction, which further aids in minimizing the segregationof larger aggregate materials as they are handled.

Also, the eight sided construction of the upper portions of theperimeter wall 32 reduces material from collecting or stagnating in thetypical square corners of typical prior art four sided hopper inserts.

Additionally, any aggregate material that does tend to collect as itflows downward toward the lower corners 55A-55D of the four sidedopening 36 is deflected laterally inward by the lower baffles 56A-56D asthat material nears the lower outlet opening 36.

All of these features working together contribute to the elimination orreduction of the collection of segregated aggregate material along theleft and right edges of the conveyor opening 64 into which the materialflows when it flows out of the lower opening 36 of the hopper insert 22.

Additionally, the hopper insert 22 is designed to prevent or reduce thepossibility of asphalt material plugging the grate 86 or bridging thegrate 86. First, the downward outward flare of the opposed upper baffles76 and 78 as seen in FIG. 4 tends to prevent the pile of asphaltmaterial from wedging against the baffles 76 and 78 and thus aids inpreventing plugging or bridging over of the grate 86. Additionally, thepresence of the grate bypass zones such as 97, 98 and 100 provides aflow path for the asphalt material in the event the grate 86 doespartially or completely plug, thus allowing a paving job to continueuntil the hopper insert 26 can be cleaned out to remove any plugging.

The upper baffles 76 and 78 will cause most of the asphalt materialloaded into the hopper insert 22 to flow between the baffles 76 and 78,even when filling the hopper insert to the optional larger fill level ofFIG. 7, thus substantially minimizing the collection of larger stones oraggregate material adjacent the side walls 42 and 44 of the hopperinsert as the material flows downward from the upper opening 34 to thelower opening 36.

Dual Capacity Modes

Another feature provided by the upper baffles 76 and 78 is the abilityto load the hopper insert to either one of two optional loadingcapacities.

The dual capacity feature of the hopper insert 22 is best understood incomparing FIGS. 6 and 7. FIGS. 6 and 7 schematically illustrate asmaller and larger optional fill level, respectively, for the hopperinsert 22.

In the smaller fill level schematically illustrated in FIG. 6, theasphalt material is deposited on top of the grate 86 only between thetwo upper baffles 76 and 78 without allowing the asphalt material tooverflow the upper baffles 76 and 78. Thus a cross-section of theasphalt pile will tend to take the shape shown in FIG. 6 where thematerial is piled highest in the interior zone 84 between the upperbaffles 76 and 78 and the pile of asphalt material may achieve itsnatural angle of repose 29 on its top surface only between the baffles76 and 78. Below the level of the lower edges 102 and 104 of baffles 76and 78, the asphalt material can spread out to the entire cross-sectionof the hopper insert 22, but the lateral volumes 80 and 82 between thebaffles and the perimeter wall are not filled.

The optional second greater fill level is achieved by allowing theasphalt material to overflow the upper baffles 76 and 78 so that theasphalt material is also received within the lateral volumes 80 and 82as seen in FIG. 7.

Thus, by the presence of the upper baffles 76 and 78, the operator ofthe material transfer vehicle 14 can readily visually observe andcontrol the maximum fill level of the hopper insert 22 to achieve aselected one of the two optional fill levels. As will be understood bythose skilled in the art, in some situations, it may be undesirable forthe paving machine 26 to carry the full weight of the hopper insert 22filled to the optional greater fill level, and thus a controllable knownlower fill level is easily achieved by simply observing the asphaltmaterial and terminating the load before the asphalt material is allowedto overflow the upper baffles 76 and 78.

EXAMPLE

In one embodiment of the hopper insert 22 the open lower end 36 may havea width 72 of approximately 48 inches and a length 74 of approximately54 inches which substantially corresponds to the dimensions of a typicalconveyor opening 64 as seen in FIG. 1A. The lateral spacing 108 betweenupper baffles 76 and 78 will have a maximum value in the centralportion, and as seen in FIG. 4 will be different at the top of thebaffles as compared to the bottom of the baffles. Thus between thecentral portions 76B and 78B of the baffles 76 and 78 as seen incross-section in FIG. 4, the baffles may have a lower baffle spacing108A at their lower edges of approximately 70 inches and an upper bafflespacing 108B of approximately 60 inches.

Then, at the forward and rearward walls 38 and 40 the upper bafflespacing 108B may taper down to a minimum value 108B′ with acorresponding tapered reduction in the lower spacing 108A.

The open upper end 34 of hopper insert 22 may have a width 116 ofapproximately 118 inches, and a length 118 of approximately 100 inches.

The hopper insert 22 may have a height 54 above the elevation of lowerend opening 36 of approximately 53 inches at the rear wall portion 40and approximately 63 inches at the forward wall portion 38.

The baffles 76 and 78 may extend a distance 94 of approximately 18inches above the grate 86, and the lower edges 102 and 104 of thebaffles 76 and 78 may be located a distance 106 of approximately 6inches below the upper edge of the adjacent side walls of the peripheralwall 32. The grate upper surface 92 may be arranged substantiallyparallel to the top edge 60 of the perimeter wall 32, thus providing aslight rearward tilt of the grate upper surface 92.

With the hopper insert 22 dimensioned as just described in this example,when the hopper insert 22 is filled to the first lower fill levelschematically illustrated in FIG. 6, it will have a fill volume ofapproximately 9.2 yd³.

When the hopper insert 22 is filled to the optional second larger filllevel schematically illustrated in FIG. 7, wherein the asphalt materialis allowed to overflow the upper baffles 76 and 78 thus filling thelateral volumes 80 and 82, the volume of material contained within thehopper insert 22 is approximately 11 yd³.

Thus the use of the upper baffles 76 and 78 provides a dual loadingcapacity without the use of an add-on extension as is typically used inthe prior art. This avoids the problem of having to bolt on the add-onextension or of the unavailability of the add-on extension when it isneeded, and it avoids the time delay involved in adding a bolt-onextension to a hopper insert. And by appropriate design, passiveremixing is provided as the material flows through the hopper insertwithout any additional operating cost.

Optional Features Of FIGS. 8-10

If even greater capacity is required for the hopper insert 22 a verticalextension module 120 may be bolted onto the upper end of hopper insert22 as schematically illustrated in FIG. 8. The vertical extension module120 may have a shape in plan view substantially identical to the shapeof the top end of hopper insert 22 and can be bolted to the hopperinsert 22 as a module in a known manner.

Additionally, in some job applications where severe problems ofaggregate segregation occur during the transport of the aggregatematerial to the job site, it may be desired to add an active remixingmodule 122 to the lower end of the hopper insert 22 as schematicallyillustrated in FIG. 9.

FIG. 10 shows a schematic plan view of the active remixing module 122which may for example include two conical augers 124 and 126 extendinglengthwise near the side walls 128 and 130 of the module 122. Theplacement of the augers adjacent the side walls 128 and 130 will providean active remixing of any larger aggregate materials that havesegregated and collected adjacent the hopper insert side walls 42 and44, thus preventing lines of segregated material from forming adjacentthe lengthwise sides of conveyor opening 64.

The auger 126 is schematically illustrated in dashed lines in FIG. 9,along with a hydraulic drive motor 132. Each of the augers will have adrive motor 132, and the drive motors may be powered from the hydraulicsystem of the paving machine 26. Optionally electric drive motors or anyother suitable drive power source may be used for the augers.

The active remixing module 122 may include an upper flange 134 thatconnects to the flange 54 of hopper insert 22. The module 122 may have alower flange 136, similar in shape to flange 54 of hopper insert 22, forresting on the floor 62 of paving machine 26, with the open bottom endof the module 122 opening into the conveyor opening 64.

For those extreme job situations requiring the additional remixingfunction of the active remixing module 122, the module 122 may be usedonly when needed and in these extreme situations the active remixing isproviding at the last point of handling of the asphalt material beforeit is actually received on the conveyor 28 of the asphalt paving machine26, thus providing the active remixing at the most effective point inthe flow path of the material. This is contrasted to various prior artsystems which use active remixing at earlier stages of the materialhandling.

Thus it is seen that the apparatus and methods of the present inventionreadily achieve the ends and advantages mentioned as well as thoseinherent therein. While certain preferred embodiments of the inventionhave been illustrated and described for purposes of the presentdisclosure, numerous changes in the arrangement and construction ofparts and steps may be made by those skilled in the art, which changesare encompassed within the scope and spirit of the present invention asdefined by the appended claims.

1-25. (canceled)
 26. A method of passive mixing of asphalt material witha hopper insert for an asphalt paving machine, the hopper insertincluding a larger upper open end and a smaller lower open end so thatthe hopper insert is funnel shaped, the method comprising: (a) receivingthe asphalt material on top of a grate located nearer to the upper endthan to the lower end of the hopper insert; (b) reducing an averageclump size of the asphalt material as at least a portion of the asphaltmaterial passes through the grate; and (c) discharging the asphaltmaterial out the smaller lower open end of the hopper insert onto aconveyor of the asphalt paving machine.
 27. The method of claim 26,wherein: step (a) further comprises piling the asphalt material on thegrate to a depth of at least 12 inches to increase a weight forcing theasphalt material through the grate.
 28. The method of claim 27, wherein:step (a) further comprises retaining the piled asphalt material on thegrate with at least two opposed lateral retainer walls on opposite sidesof the grate, the retainer walls being laterally spaced from aperipheral wall of the hopper insert.
 29. The method of claim 28,further comprising: laterally spreading the asphalt material todifferent widths along a length of the grate via a variable lateralspacing between the retainer walls.
 30. The method of claim 28, furthercomprising: reducing bridging of the asphalt material between theretainer walls via a downward outward flare of the retainer wallsrelative to each other.
 31. The method of claim 26, wherein: step (a)further comprises retaining at least a portion of the asphalt materialon the grate between at least two opposed lateral retainer walls onopposite sides of the grate, the retainer walls being laterally spacedfrom a peripheral wall of the hopper insert; and further comprising:filling the hopper insert to a smaller one of two optional fill levelsby depositing the asphalt material only between the two retainer wallswithout allowing the asphalt material to overflow the retainer walls.32. The method of claim 26, wherein: step (a) further comprisesretaining at least a portion of the asphalt material on the gratebetween at least two opposed lateral retainer walls on opposite sides ofthe grate, the retainer walls being laterally spaced from a peripheralwall of the hopper insert; and further comprising: filling the hopperinsert to a larger one of two optional fill levels by depositing theasphalt material between the two retainer walls and allowing the asphaltmaterial to overflow the retainer walls so that the deposited asphaltmaterial is also received within a lateral volume between each of theretainer walls and the peripheral wall of the hopper insert.
 33. Themethod of claim 26, further comprising: bypassing at least a bypassportion of the asphalt material around the grate as the asphalt materialflows downward from the larger upper open end to the smaller lower openend.